It is well known that a tachyonic mode appears in the spectrum of Yang—Mills theory with a static uniform magnetic field, and that the free energy has an (unstable) minimum at finite magnetic field. It is argued that spontaneous generation of magnetic field does not take place at high temperature due to nonperturbative magnetic screening. Furthermore, the dispersion relation for gauge field flu...

In this survey article we discuss some aspects of finite variable logics. We translate some well-known fixed-point logics into the infinitary logic L∞ω, discussing complexity issues. We give a game characterisation of L∞ω, and use it to derive results on Scott sentences. In this connection we consider definable linear orderings of types realised in finite structures. We then show that the Craig...

Variable-step (VS) second derivative $k$-step $3$-stage Hermite--Birkhoff--Obrechkoff (HBO) methods of order $p=(k+3)$, denoted by HBO$(p)$ are constructed as a combination of linear $k$-step methods of order $(p-2)$ and a second derivative two-step diagonally implicit $3$-stage Hermite--Birkhoff method of order 5 (DIHB5) for solving stiff ordinary differential equations. The main reason for co...

The atmospheric refractive index consists of both real and imaginary parts. The intensity of refractive index fluctuations is generally expressed as the refractive index structure parameter, with the real part reflecting the strength of atmospheric turbulence and the imaginary part reflecting absorption in the light path. A large aperture scintillometer (LAS) is often used to measure the struct...

We argue that in QCD, the Debye mass requires not only a mathematical definition but also a physical one and temporal axial gauge could provide for a physical screening potential for this purpose. Unfortunately, this gauge is spoiled by problem of energy conservation rather than the well known divergence due to the double pole in the longitudinal propagator. We also show that KMS condition is v...

Artificial chemistries are usually used to study what phenomena occur in a given setup, and simulators are the primary tools. This paper attempts to address a reverse question, that is, what setup is required to produce given molecules, using reasoning as the tool. We give a procedure to answer whether specified molecules can be produced in a given system described in our artificial chemistry, ...

We introduce a notion of position-space cuts of eikonal diagrams, the set of diagrams appearing in the perturbative expansion of the correlator of a set of straight semi-infinite Wilson lines. The cuts are applied directly to the position-space representation of any such diagram and compute its imaginary part to the leading order in the dimensional regulator. Our cutting prescription thus defin...

We find the high overtones of gravitational and electromagnetic quasi-normal spectrum of the Schwarzschild-de Sitter black hole. The calculations show that the real parts of the electromagnetic modes asymptotically approach zero. The gravitational modes show more peculiar behavior at large n: the real part oscillates as a function of imaginary even for very high overtones and these oscillations...